The present invention relates to a zoom lens and, in particular, relates to one such zoom lens having a pressure differential pneumatic lens drive.
Conventional zoom lenses typically include an external drive mechanism which is attached to a moveable optical lens. In such a lens, since a driving force is acting at some distance from an optical axis the base length of guide bearings are made larger than would otherwise be necessary to control tilting of the lens. It is a disadvantage of such a lens that since driving components, such as motors, gears etc., are directly mounted on the lens assembly, the lens makes noise and cannot be made to operate "silent". Another disadvantage is that the lens still has some tilt and de-centering force acting thereon, which causes undesirable viewing error.
Consequently, it is highly desirable to provide a zoom lens that substantially overcomes the above-recited disadvantages of conventional zoom lenses.